Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: Sealability between a cover member and a transparent member of an optical scanning apparatus is improved to improve dustproof performance. An optical scanning apparatus includes an elastic member 75 for sealing a portion between a cover member 70 and a glass member 90, the elastic member 75 being formed on the cover member 70 so as to surround an opening portion 42, the elastic member 75 being formed from a material that differs from that of the cover member 70. The elastic member 75 has a protrusion 75a that extends towards the glass member 90. The protrusion 75l a fills a gap between the cover member 70 and the glass member 90 by contacting the glass member 90 and being elastically deformed.

Abstract: A light scanning apparatus, including: a light source; a deflector having a rotary polygon mirror configured to deflect the light beam emitted from the light source, and a motor configured to rotate the polygon mirror; a plurality of reflecting mirrors configured to reflect the light beam to the photosensitive member; and an optical box on which the light source is mounted, wherein the optical box has an installation wall on which the deflector is installed and a support wall positioned on a side of the photosensitive member with respect to the polygon mirror, the support wall being provided with a support portion configured to support at least one reflecting mirror, a stepped portion having a plurality of steps is formed between the installation wall and the support wall, and a back surface of the stepped portion has a shape following an inside surface of the stepped portion.

Abstract: Sealability between a cover member and a transparent member of an optical scanning apparatus is improved to improve dustproof performance. An optical scanning apparatus includes an elastic member for sealing a portion between a cover member and a glass member, the elastic member being formed on the cover member so as to surround an opening portion, the elastic member being formed from a material that differs from that of the cover member. The elastic member has a protrusion that extends towards the glass member. The protrusion fills a gap between the cover member and the glass member by contacting the glass member and being elastically deformed.

Abstract: An optical scanning apparatus includes a polygonal mirror configured to deflect a light beam emitted from a light source such that the laser beam scans a member to be scanned, a drive motor configured to rotate the polygonal mirror, aboard on which the polygonal mirror and the drive motor are mounted, an installation portion where the board is installed, a rubber member provided between the board and the installation portion, and an adjustment unit configured to position on the board with respect to the installation portion and to adjust inclination of the board with respect to the installation portion by deforming the rubber member.

Abstract: An image forming apparatus including: a photosensitive member; a process member configured to act on the photosensitive member; and a light scanning apparatus configured to emit a light beam to the photosensitive member. The light scanning apparatus includes: a light source; a rotary polygon mirror; a first signal generating unit configured to receive the light beam deflected by the rotary polygon mirror to generate a first signal indicating a scan starting position; and a second signal generating unit configured to generate a second signal based on a rotation angle of the rotary polygon mirror. A lighting-up timing of the light source for generating the first signal is determined based on a number of the second signals after a voltage for image formation is applied and a relationship between the first signal and the second signal is obtained before the voltage is applied and after the rotary polygon mirror is rotated.

Abstract: A light scanning apparatus, including: an optical box configured to hold a deflector and an optical member; and a cover, the optical box including: a concave-shaped cut-away portion formed from a top portion of a side wall toward a bottom portion; and a connecting wall which stands from the bottom portion of the optical box and is bent and branched from the cut-away portion to an inside of the optical box so as to cross over the cut-away portion, the cover including a dustproof member sandwiched between the cover and the side wall and between the cover and the connecting wall which a cable passes, wherein a height of a distal end of the connecting wall, which the cable passes, from the bottom portion is larger than a height of a base portion of the cut-away portion from the bottom portion.

Abstract: A light scanning apparatus, including: a light source; a rotary polygon mirror configured to deflect a light beam emitted from the light source; a plurality of optical members configured to guide the light beam, which is deflected by the rotary polygon mirror, to a photosensitive member; a drive motor configured to rotate the rotary polygon mirror; an optical box to which the light source is attached, the optical box containing the rotary polygon mirror, the drive motor, and the optical members; and a dynamic vibration absorber mounted inside the optical box and configured to be vibrated by vibrations of the optical box, wherein the plurality of optical members are supported on a bottom portion of the optical box, and the dynamic vibration absorber is disposed on the bottom portion of the optical box at a position between at least two adjacent optical members among the plurality of optical members.

Abstract: A laser holder includes a bridge portion connected to a holding portion via two projecting portions so as to bridge the two projecting portions, and the bridge portion includes a contacting portion configured to come into contact with the optical box by being pressed against an optical box by a screw head of a second fixing screw.

Abstract: A light scanning apparatus, including: a light source configured to emit a light beam; and a rotary polygon mirror configured to deflect the light beam emitted from the light source so that the light beam scans a surface of a photosensitive member, wherein the rotary polygon mirror is formed in a four-sided polygon, and wherein a difference between a pair of diametrically opposed interior angles of the rotary polygon mirror is larger than 0.03°, and a difference between another pair of diametrically opposed interior angles of the rotary polygon mirror is 0.03° or less.

Abstract: Sealability between a cover member and a transparent member of an optical scanning apparatus is improved to improve dustproof performance. An optical scanning apparatus includes an elastic member 75 for sealing a portion between a cover member 70 and a glass member 90, the elastic member 75 being formed on the cover member 70 so as to surround an opening portion 42, the elastic member 75 being formed from a material that differs from that of the cover member 70. The elastic member 75 has a protrusion 75a that extends towards the glass member 90. The protrusion 75a fills a gap between the cover member 70 and the glass member 90 by contacting the glass member 90 and being elastically deformed.

Abstract: An image forming apparatus including: a photosensitive member; a charging unit; a light scanning apparatus configured to emit a light beam to scan the photosensitive member to form a latent image; and a developing unit configure to develop the latent image. The light scanning apparatus includes a light source, a rotary polygon mirror, a light receiving unit, and a signal generating unit. An incident timing when the light beam deflected by the polygon mirror enters the light receiving unit after the photosensitive member is charged by the charging unit and after a voltage is applied to a toner carrying member by the developing unit is identified based on the number of second signals generated by the signal generating unit between the first signal and the first signal generated by the light receiving unit before the photosensitive member is charged and before the voltage is applied to the toner carrying member.

Abstract: A light scanning apparatus, including: an optical box configured to hold a deflector and an optical member; and a cover, the optical box including: a concave-shaped cut-away portion formed from a top portion of a side wall toward a bottom portion; and a connecting wall which stands from the bottom portion of the optical box and is bent and branched from the cut-away portion to an inside of the optical box so as to cross over the cut-away portion, the cover including a dustproof member sandwiched between the cover and the side wall and between the cover and the connecting wall which a cable passes, wherein a height of a distal end of the connecting wall, which the cable passes, from the bottom portion is larger than a height of a base portion of the cut-away portion from the bottom portion.

Abstract: A light scanning apparatus including: an optical box configured to hold a light source and contain a deflecting device configured to deflect a light beam to scan the photosensitive member; and an electric wire bundle electrically connected to the deflecting device, the electric wire bundle being laid in a space between an outer wall and an inner wall of the box, wherein the electric wire bundle extends over the inner wall from the inside of the inner wall, is laid in the space, and extends over the outer wall from the space to the outside of the box, and a portion at which the bundle extends over the outer wall is provided closer to an opening portion of an image forming apparatus than a portion at which the bundle extends over the inner wall when the light scanning apparatus is mounted to a mounting portion of the image forming apparatus.

Abstract: A cover member to be attached to a housing including a bottom portion and a side wall, the cover member including: a closing surface configured to close an opening surrounded by the side wall; at least three protruding portions protruding from the closing surface so as to be located on an inside of the housing; and a protection portion configured to protect a circuit board fixed to the side wall, the protection portion having: a first opposed portion opposed to the circuit board and provided to stand on the closing surface; a second opposed portion opposed to the circuit board and protruding with respect to the first opposed portion away from the circuit board; and a connecting portion configured to connect the first opposed portion and the second opposed portion, wherein a length of the at least three protruding portions is larger than a length of the first opposed portion.

Abstract: A light scanning apparatus, including: a light source; a deflector configured to deflect the light beam from the light source to scan a photosensitive member; an optical member configured to guide the light beam; a housing including a housing engaging portion and a supporting portion configured to support the optical member; a leaf spring including a pressing portion and a leaf spring engaging portion; and an abutment portion, wherein, in a process in which the housing engaging portion and the leaf spring engaging portion are moved from a second state in which the leaf spring engaging portion is not engaged with the housing engaging portion to a first state in which the leaf spring engaging portion is engaged with the housing engaging portion, the pressing portion is moved from the abutment portion to the optical member.

Abstract: An image forming apparatus including: a photosensitive member; a charging unit; a light scanning apparatus configured to emit a light beam to scan the photosensitive member to form a latent image; and a developing unit configure to develop the latent image. The light scanning apparatus includes a light source, a rotary polygon mirror, a light receiving unit, and a signal generating unit. An incident timing when the light beam deflected by the polygon mirror enters the light receiving unit after the photosensitive member is charged by the charging unit and after a voltage is applied to a toner carrying member by the developing unit is identified based on the number of second signals generated by the signal generating unit between the first signal and the first signal generated by the light receiving unit before the photosensitive member is charged and before the voltage is applied to the toner carrying member.

Abstract: A light scanning apparatus, including: a light source; a deflector having a rotary polygon mirror configured to deflect the light beam emitted from the light source, and a motor configured to rotate the polygon mirror; a plurality of reflecting mirrors configured to reflect the light beam to the photosensitive member; and an optical box on which the light source is mounted, wherein the optical box has an installation wall on which the deflector is installed and a support wall positioned on a side of the photosensitive member with respect to the polygon mirror, the support wall being provided with a support portion configured to support at least one reflecting mirror, a stepped portion having a plurality of steps is formed between the installation wall and the support wall, and a back surface of the stepped portion has a shape following an inside surface of the stepped portion.

Abstract: A light scanning apparatus including: an optical box configured to hold a light source and contain a deflecting device configured to deflect a light beam to scan the photosensitive member; and an electric wire bundle electrically connected to the deflecting device, the electric wire bundle being laid in a space between an outer wall and an inner wall of the box, wherein the electric wire bundle extends over the inner wall from the inside of the inner wall, is laid in the space, and extends over the outer wall from the space to the outside of the box, and a portion at which the bundle extends over the outer wall is provided closer to an opening portion of an image forming apparatus than a portion at which the bundle extends over the inner wall when the light scanning apparatus is mounted to a mounting portion of the image forming apparatus.